1. Technical Field
The present invention relates in general to networks and, in particular, to a method and system for routing communication between nodes of a network containing multiple nodes. Still more particularly, the present invention relates to a network in which communication between nodes of a system area network (SAN) is filtered by traffic type, for example, to avoid errors arising from multiple nodes sharing the same node identifier.
2. Description of the Related Art
A system area network (SAN) is a collection of interconnected processor and peripheral nodes that operate in concert as a data processing system. The SAN topology advantageously permits large data processing systems customized to the processing, storage and I/O requirements of particular installations to be readily constructed through the interconnection of desired numbers of processor and peripheral nodes via backplane connections or inter-cabinet cables.
To promote reliable, efficient communication, a SAN generally logically and physically isolates processor buses and input/output (I/O) buses in separate nodes. Communication between the processors and peripherals in a SAN must therefore be routed between nodes, for example, utilizing unique node identifiers (IDs) assigned by firmware at system startup.
The conventional method of routing communication in a SAN is subject to errors if, following system startup, two SANs are interconnected, for example, by an intercabinet cable. Errors arise because the node IDs assigned in each of the smaller SANs may not be unique throughout the combined system. As a result, communication in the combined system may be routed incorrectly, possibly causing data corruption and/or other undesirable errors.
The present invention therefore recognizes that it would be useful and desirable to provide an improved method and system of inter-node communication in a SAN in which all of the nodes may not have unique node IDs.